The present invention relates generally to rotating disk information storage systems and, more particularly, to a magnetic disk storage system in which the magnetic transducer is mounted on a slider in physical contact with the storage medium at an operating speed which utilizes the tribo-attractive effect to maintain the slider in physical contact with the storage medium surface.
In magnetic storage systems, an information bit is stored by focusing a magnetic field to a small volume on the disk to align the magnetic domains in that volume to a desired orientation. In optical storage systems, an information bit is stored by focusing a laser beam onto a small spot on the optical disk to heat the medium and thus effect a physical change in the medium material at that spot. In the case of magneto-optic storage systems, the heat generated by the laser beam causes the magnetic domains at the spot location to be aligned with an applied magnetic field. In all moving disk storage systems, the demand for increased storage capacity is presently being met by increasing the areal bit density on the storage disk.
In magnetic disk storage systems, increase of areal bit density requires the reduction of three basic parameters, the magnetic write transducer (head) gap length, the thickness of the magnetic storage media and the head to disk separation. Given a specified gap length and media thickness, the smaller the head-disk separation, i.e., the lower the head flying height, is, the smaller the bit cell size which can be achieved is. The limit of lower flying height is contact recording, in which the slider is in physical contact with the rotating magnetic disk, i.e., the slider is sliding or rubbing continuously on the disk surface and the read/write transducer is as close as the edge of the slider can be to the disk surface. U.S. Pat. No. 4,819,091 to Brezoczky et al, assigned to the instant assignee, discloses a magnetic contact recording system comprising a magnetic read/write head mounted on a slider fabricated from a single crystal material which is in physical contact with the rotating storage medium. A tribo-attractive force is generated between the moving disk surface and the slider which counteracts the lifting force generated by the moving air layer adjacent the disk surface and which allows contact recording and reading of data without excessive wear to either the magnetic head and slider or the recording medium.
U.S. Pat. No. 4,901,185 to Kubo et al, assigned to Kabushiki Kaisha Toshiba, discloses a rotating magnetic disk storage system wherein a trailing edge of a slider is maintained in contact with the surface of a rotating magnetic disk. The slider is suspended over the rotating disk by a set of gimbal arms which include a leaf spring means to impart a rotational force to the slider to bring a trailing portion of the slider air bearing surface into contact with the moving magnetic disk surface. A magnetic head is located on or embedded in the face of the slider trailing edge with the surface of the magnetic head near to but not in contact with the disk surface to prevent wear of the head surface. Wear of the slider contact surface and the disk is minimized by use of a disk lubricant and reduction of the disk rotational speed.
None of the references disclose a contact data storage system having high speed moving magnetic media and utilizing a slider fabricated of a polycrystalline material which, in conjunction with the moving magnetic media, generates a restoring force allowing the slider to be maintained in physical contact with the disk surface under a zero or negative external load.